To appear in: The Oxford Handbook of Leibniz, ed. Maria Rosa Antognazza (Oxford University Press) Chapter 4 The Actual World Donald Rutherford The contrast between the actual and the possible is one of the most important distinctions in Leibniz s philosophy. On it rests the central thesis of his theodicy (that the actual world is the best of all possible worlds), as well as other key doctrines, including his solution to the problem of the labyrinth of the continuum. The same distinction, though, is also the source of longstanding interpretative problems. Among these are the ontological status of the possible, the circumstances under which possibles become actual, the incompossibility of possibles, and the continued dependence of actual things on God. That the possible possesses a form of reality is a foundational tenet for Leibniz. If this were not the case, he believes, there would be no basis for the eternal truths of mathematics and metaphysics, or for true propositions about the essences of things. The reality of the possible is also the starting point for Leibniz s account of the ultimate origination of things : if the possible were not real, there would be no ground for the existence of actual things. 1 Leibniz s thinking on this topic is guided by the principle of sufficient reason: that nothing happens without it being possible for someone who knows enough to give a reason sufficient to determine why it is so and not otherwise. Assuming this principle, he writes, the first question we have the right to ask will be, why is there something rather than nothing? For nothing is simpler and easier than 1 See in particular the essay On the Ultimate Origination of Things, dated 23 November 1697 (GP VII 302-8/AG 149-55).
2 something. Then, supposing that some things exist, we must be able to give a reason for why they must exist in this way, and not otherwise. 2 The two most basic questions of metaphysics are thus: Why is there something rather than nothing? And, why do certain things exist, while other equally possible things do not? Leibniz s response to these questions begins from the assumption that answers to them cannot be found within the things that make up the universe, for it is the universe itself the series of all actual things that stands in need of explanation. Such an explanation, therefore, can only be found in an extramundane reason: a substance outside the series of contingent things, which is a necessary being, carrying the reason for its existence within itself. Otherwise, we would not yet have a sufficient reason where one could end the series. And this ultimate reason for things is called God (PNG 8; GP VI 602/AG 210). Leibniz s assertion that God is the ultimate ground of the existence of the actual world is unremarkable. It records his conviction that the explanatory regress set up by the principle of sufficient reason must terminate in a necessary being that is the ground of its own existence. Yet Leibniz s certainty on this point gives new force to the two questions with which we began. If God is a necessary being, sufficient unto himself, why does a created world exist at all? Why not the simpler alternative of nothing? And supposing that something exists, why just the assorted contents of the world we take to be actual, rather than the manifold possibilities of things that do not exist? Leibniz s answers to these questions are the topic of this chapter. Section 1 addresses his answer to the first question, focusing on his claim that every possible has a propensity to exist, proportional to its degree of perfection, and the consistency of this claim with the dogma that God creates contingent things ex nihilo through the exercise of his free will. Sections 2 and 3 2 Principles of Nature and of Grace (hereafter: PNG), 7 (GP VI 602/AG 210).
3 examine Leibniz s answer to the second question from the perspective of his doctrine that not all possibles are compossible, and, hence, that God is limited to creating that possible world which contains the greatest total perfection. Section 4 considers in more detail how Leibniz conceives of the best possible world and his efforts to reconcile a variety of distinguishable criteria of goodness. Section 5, finally, takes up his account of the continual dependence of the actual world on God and his defense of the traditional doctrine of God s concurrence in all the actions of created things. 1. From Possibility to Actuality Leibniz affirms the theologically orthodox view that, with the exception of God, whatever exists does so because it is has been created by God. He also accepts that God creates by a free choice of his will, suggesting that the absence of a created world is a possible state of affairs. 3 Yet, he immediately follows this with the assertion that this is not a state of affairs that would be realized by God, or which is consistent with a correct understanding of God s nature. God s will, he says, is in no way indifferent or indeterminate: his will is always decided, and it can only be decided by the best (T 337; GP VI 315/H 328). Leibniz s justification for this claim is that the perfection realized in created things is a reason for God to create them. By virtue of its goodness, God s will aims at communicating himself (T 228; GP VI 253/H 269), that is, it has as an end the production of perfection. Thus, antecedently, God wills the existence of all things in proportion to their degree of perfection, while his consequent or decisive will is to create the best: the greatest perfection that can be realized. 4 3 Theodicy (hereafter: T), 336 (GP VI 314/H 327). 4 T 22-23. To Des Bosses, Leibniz writes: In my judgment, unless there were a best series, God clearly would have created nothing, since he cannot act without a reason, or prefer
4 Such is Leibniz s official account of the ultimate origination of things as it appears in the Theodicy. In unpublished essays from the 1680s and 1690s, we encounter a somewhat different story, which some commentators have seen as pointing to a less orthodox position. 5 In these works, Leibniz emphasizes, as the ground of existence, the inherent demand (exigentia), claim (praetensio), or tendency (tendentia) of any possible to exist (GP VII 303-5). Given this demand or tendency to exist, present in varying degrees in all possibles, there is a competition among them. On the assumption that the existence of some precludes the existence of others, not all can exist. Consequently, there is a process of selection whereby the greatest collection of compossibles those possibles that can coexist reaches actuality, leaving the rest in a condition of mere possibility (A VI.4, 1442-3). Because this account is found primarily in Leibniz s private writings, it is tempting to see it as an expression of his deep, or esoteric, metaphysics, which is in tension with more orthodox, public presentations of his views. Such a reading, however, is untenable. Leibniz alludes to the account in Theodicy, 201 and stresses that it is based on a figurative way of speaking: the less perfect to the more perfect alternative (Look-Rutherford, 212-13). Leibniz defines perfection (or metaphysical good ) as the magnitude of positive reality considered as such ( Monadology [hereafter: Mon], 41; GP VI 614/AG 218), or the quantity of essence (GP VII 303). Thus, in creating the greatest total perfection, God creates the world in which there is in actuality as much reality as possible (GP VII 306). 5 David Blumenfeld, Leibniz s Theory of the Striving Possibles, Studia Leibnitiana 5 (1973): 163-77. The main texts (with dates assigned by A) include: On First Truths, 1680 (A VI.4, 1442-3); General Notions, ca. 1683-5 (A VI.4, 550-7); On the Reason Why These Things Should Exist Rather Than Any Others, 1689 (A VI.4, 1634-5); On the Ultimate Origination of Things, 1697 (GP VII 302-8). See also the undated summary at C 533-5/GP VII 289-91, translated as A Résumé of Metaphysics, in Leibniz, Philosophical Writings, ed. G.H.R. Parkinson and trans. Mary Morris and G.H.R. Parkinson [hereafter: MP] (London: J.M. Dent & Sons, 1973), 145-7.
5 One may say that as soon as God has decreed to create something there is a struggle among all the possibles, all of them laying claim [pretendans] to existence, and that those which, being united, produce most reality, most perfection, most intelligibility carry the day. It is true that all this struggle can only be ideal, that is to say, it can only be a conflict of reasons in the most perfect understanding, which cannot fail to act in the most perfect way, and consequently to choose the best. (GP VI 236/H 253). The demand or claim possibles make for existence refers, strictly, to the magnitude of the reason they offer God to create them. Possibles have a greater tendency to exist to the extent that they represent a greater degree of perfection, which means that, other things being equal, God has a greater reason to create them. Reflection on the principles of Leibniz s metaphysics confirms that this is the only position he could take. Striving or tendency is a manifestation of the power of primary created beings: substances. Mere possibles have no power, because they are not actual. Hence, the images of possibles striving in the mind of God for creation can only be a metaphor referring to the weight of the reasons they offer for creation. With the exception of God, possibles do not exist of themselves; their reality is limited to that which they possess as objects of divine ideas. To become actual or existent, things corresponding to those ideas must be created by God. 6 6 Leibniz makes this clear in one of the private texts: And every possible involves not only possibility but also an actual endeavor of existing [conatum actu existendi], not as though those things which do not exist have endeavor [conatum], but because in this way the ideas of essences in God demand to be actually existing; thereafter, God freely decides to choose whatever is most perfect. From this, it is obvious that the essences of things depend on the divine nature, existences on the divine will; for nothing can obtain existence by its own force, but only by the decree of God (A VI.4, 557).
6 2. Compossibility No finite thing exists unless created by God, but, according to Leibniz, God does not create all possible things. Although all possibles present God with reasons to create them, some of these reasons must prevail over others, because not all possibles are compossible. Thus, God must make a choice of some over others, opting for that collection of compossibles that is, overall, the best. Leibniz crafted his position as a response to Spinoza s metaphysics. It is Spinoza s view that every finite thing that can exist does exist as a necessary expression of God s infinite power. 7 Leibniz rejects this view as inconsistent with an understanding of God as a supremely perfect being whose actions evidence a fundamental justice with respect to creation. A creator who merits being worshipped, whose character is appropriate for emulation by human beings, must be one who acts for the greatest reason, choosing the best because it is the best. As Leibniz sees it, an impersonal, all-powerful God, such as Spinoza describes, severs the essential connection between theology and morality. Our moral compass takes its direction from the justice God exercises in creation, the rightness of his action consisting in its being a free choice of the best from among a set of mutually exclusive alternatives. 8 Although Leibniz is satisfied to assert this conception of God against Spinoza s, he also seeks confirmation of it through his account of the ultimate origination of things. Principally, this 7 Spinoza, Ethics, Part I, Prop. 16. 8 He records the following in December 1676, during his most intense engagement with Spinoza s views: If all possibles were to exist, there would be no need of a reason for existing, and mere possibility would be enough. So there would not be a God, except in so far as he is possible. But a God of the kind in whom the pious believe would not be possible, if the opinion of those who believe that all possibles exist were true (A VI.3, 582/Parkinson, 105). See also Discourse on Metaphysics (hereafter: DM), 2; T 173-174.
7 comes through the doctrine that a choice is forced upon God by the fact that not all possibles are compossible. 9 If God s intellect represents a set of possibles as incompossible, then God cannot, in a single act, render those possibles actual. Leibniz finds in this explanation a basis for his rejection of Spinoza s metaphysics. If possibles, by virtue of what they are, organize themselves into mutually exclusive sets of compossibles possible worlds then God is limited to creating one from among those sets: that which is the best. By reframing the problem in this way, Leibniz raises the hope of a non-circular argument against Spinoza s conception of God. This argument obviously hinges on Leibniz s ability to delineate the sense in which possibles may be incompossible. He was aware of the difficulty he faced in this regard. If the most basic forms of possibility are simple absolute essences, represented by purely positive terms, then there is no basis for incompossibility: all such terms, and any conjunctions of them, are consistent with each other. 10 In later writings, Leibniz takes himself to have found a solution to this problem, an account of incompossibility that blocks the inference to the existence of all possible things. Central to his account is the idea that the possibles that segregate themselves into compossible sets are possible substances, represented by complete concepts. Thus, possible worlds can be understood, minimally, as consistent sets of complete concepts. Still, Leibniz s formulation of this doctrine is far from clear, and his unclarity has spawned an extensive debate in the literature. On one side of the debate, defenders of the logical interpretation construe the relation of 9 For a late statement of the position, see his letter to Bourguet of December 1714 (GP III 573/L 662). 10 He acknowledges the problem in the 1680 essay On First Truths : to this point, people have been ignorant of the source of the incompossibility of different things, or of what could make it the case that different essences conflict with each other, since all purely positive terms seem to be compatible with each other (A VI.4, 1443).
8 compossibility in terms of logical consistency: possible substances are compossible if and only if the supposition of their joint existence is logically consistent. On the other side, defenders of the lawful interpretation hold that possible substances are compossible if and only if they can be conceived as connected under some set of suitable natural laws. 11 Both sides in the debate highlight plausible aspects of Leibniz s position, but in the end neither makes a compelling case for its reading. The strength of the logical interpretation is that it identifies incompossibility with a strict limitation on the exercise of God s power. If two complete concepts are incompossible, then the supposition of their joint existence is inconsistent and both cannot be actualized. If some complete concepts are incompossible in this sense, then God cannot, consistent with his own rationality, determine the existence of all possible things. It is doubtful, though, whether defenders of the logical interpretation succeed in showing that any complete concepts are incompossible in this sense. 12 Much is made of the idea that there is an implicational relation among the complete concepts of substances belonging to the same world, such that the existence of one substance entails the existence of all its worldmates and the nonexistence of any substances not belonging to that world. At bottom, however, this implication rests on the assumption that the substances belonging to the same world express each other, meaning that there is a lawful relation between what can be said about one and the other, and that 11 For an overview of the debate, see James Messina and Donald Rutherford, Leibniz s Theory of Compossibility, Philosophy Compass 4 (2009): 962-9; Margaret Wilson, Compossibility and Law, in Causation in Early Modern Philosophy, ed. Steven Nadler (University Park, PA: Pennsylvania State University Press, 1993), 119-33. 12 A single text, dated ca. 1687-96, supports the reading of incompossibility as logical inconsistency: The compossible is that which, with another, does not imply a contradiction (A VI.4, 867/Grua, 325). More frequently, Leibniz explicates incompossibility in terms of things being incompatible (incompatibilia) with respect to spatiotemporal or causal order. See C 534/MP 145-6, and the discussion in section 3 below.
9 they fail to express the substances belonging to other worlds. Given this, a failure of compossibility does not amount to logical inconsistency, but only a lack of order or lawfulness. 13 If this is correct, then the logical interpretation of compossibility does not differ materially from the lawful intepretation. The crux of the latter reading is that, with respect to God s absolute power, the supposition of the joint existence of any two substances is logically consistent. However, it does not follow from this that any two substances are compossible, for compossibility requires in addition that their states be related by some set of suitable laws. 14 The qualification of these laws as suitable is necessary, for Leibniz asserts that a rule can be devised to fit any set of data; in this sense, any set of substances can be related by some law. 15 But such a law would not have the generality he associates with the exercise of God s reason. Any law by which substances are rendered compossible must be a law defined in terms of general properties of the substances and not merely brute facts determined by their particular existences. 16 13 The role of the doctrine of expression is acknowledged by defenders of the logical interpretation. See Benson Mates, The Philosophy of Leibniz: Metaphysics and Philosophy of Language (New York: Oxford University Press, 1986), 76-8, 220; Nicholas Rescher, Leibniz: An Introduction to His Philosophy (Lanham, MD: University Press of America, 1979), 49-50. According to Leibniz, it suffices for the expression of one thing in another that there be some constant law of relations, by which particulars in one can be referred to corresponding particulars in the other (C 15/MP 176-7). Cf. A II.2, 240/LA 144. 14 For an early statement of this reading, see Bertrand Russell, A Critical Exposition of the Philosophy of Leibniz. 2 nd ed. (London: George Allen and Unwin, 1937), 67; for a more elaborate development, see Gregory Brown, Compossibility, Harmony, and Perfection in Leibniz, The Philosophical Review 96 (1987), 173-203. 15 DM 6. Compare J. A. Cover and John O Leary Hawthorne, Substance and Individuation in Leibniz (Cambridge: Cambridge University Press, 1999), 134, 137. 16 God can never have a primitive particular will, that is, independent of laws or general acts of will; such a thing would be unreasonable. He cannot determine upon Adam, Peter, Judas or any individual without there being a reason for this determination; and this reason leads of necessity to some general proposition. The wise mind always acts according to principles; always according to rules (T 337; GP VI 315/H 328).
10 On this understanding of Leibniz s position, incompossibility does not track a logical restriction on the exercise of God s power. With respect to his absolute power, God could create a single substance by itself or a collection of substances whose states were disordered with respect to each other. 17 Nevertheless, compossibility does reflect constraints that God s reason imposes on the exercise of his power; specifically, it registers the fact that any actual or possible act of divine will is in conformity with the principle of order. 18 Compossible complete concepts are those that God conceives as ordered in ways necessary to make a world; incompossible complete concepts are those that fail to meet this condition. Even if God could, logically, create the latter, his will would not tend toward that end, because of the absence of the requisite order. The difficult question is how to understand the constraints that order places on the representation of substances as compossible, or capable of joint realization in a world. For proponents of the lawful interpretation, this comes down to the fact that the substances meet some general condition, such as that their states express each other, that they are connected by suitable laws, or that they harmonize with each other. 19 A set of substances will be compossible, and hence will comprise a possible world, if and only if they meet this condition. The problem with such approaches is that they remain overly general. Each of the aforementioned concepts 17 See Leibniz s comment to Des Bosses in his letter of 29 April 1715 (Look-Rutherford, 337-9). 18 Possible acts of divine will are those that figure in God s knowledge of worlds he may (but, with the exception of one, does not) create. Adams notes the relevance for Leibniz of the medieval distinction between God s potentia absoluta and potentia ordinata, the former referring to God s power considered in abstraction from his other attributes (Robert M. Adams, Leibniz: Determinist, Theist, Idealist [New York: Oxford University Press, 1994], 106, n. 36). For Leibniz, any actual or possible act of divine will is a general volition, subject to the condition of order. This means that any object of God s will is represented as distinctly thinkable in accordance with general principles (C 535/MP 146). 19 Representative of the first approach are Cover and O Leary-Hawthorne, Substance and Individuation in Leibniz; of the second, Russell, Critical Exposition; of the third, Olli Koistinen and Arto Repo, Compossibility and Being in the Same World in Leibniz s Metaphysics, Studia Leibnitiana 31 (1999), 196-214.
11 expression, lawfulness, harmony is suggestive of his view that compossible substances instantiate a distinctive order with respect to each other. Yet there has been no convincing demonstration that any of these concepts by itself is sufficient to define the notion of compossibility. Interpretations that follow this approach fail because they turn Leibniz s doctrine of compossibility on its head. In no text does he argue that substances are compossible, and hence belong to the same world, just in case they express one another, are lawfully related, or harmonize in their perceptions. Rather, in explicating the idea of compossibility, Leibniz is guided by a substantive conception of the order definitive of a world. This order is based on the spatiotemporal and causal relations that any substances must stand in if they are to be members of the same world. Giving priority in this way to the formal structure of a world forms the basis of a third approach to the problem of compossibility: the cosmological account. 20 3. The Cosmological Account That any compossible substances must have a specific order with respect to each other, and that this order places constraints on which things can exist in a world, comes out clearly in Leibniz s comparison of God to an architect who seeks to fill a given space with the most varied and elegant collection of rooms, or a tiler who lays down pieces so as to contain as many as possible in a given area (GP VII 304/AG 151). On these scenarios, the limitations on coexistence are defined not just by logical consistency, but by the geometry of space: how different shapes can be arranged with respect to each other in a given area. The implication of the analogy is that just as not all tiles can be combined on a given surface, so not all possible substances can be 20 See Rutherford, Leibniz and the Rational Order of Nature, 188-97; Messina and Rutherford, Leibniz on Compossibility.
12 combined in a given world; certain possibles are precluded from standing in the requisite relations to others. In On the Ultimate Origination of Things, Leibniz develops this line of thought in ways that suggest it is, in fact, more than an analogy. The divine mathematics that God employs in creation is a method for maximizing the amount of perfection, or reality, that can be contained within the capacity of space and time, which he identifies with the capacity of the order of possible existence (GP VII 304/AG 151). Space and time, he writes, define the receptivity or capacity of a world (GP VII 303/AG 150). This means that any things conceived to exist in the same world must be understood to have well-defined spatial and temporal relations to each other; there must be a determinate answer to the question of where and when they are with respect to each other. Consequently, for God, the problem of creation does not involve maximizing the quantity of reality absolutely, but relative to the constraints of spatial and temporal order. 21 Considerable evidence supports the link between these orders and Leibniz s conception of compossibility. Representative is his comment in a late reply to Pierre Bayle: Space and time taken together constitute the order of possibilities of one entire world, so that these orders space and time, that is relate not only to what actually is but also to anything that could be put in its place (GP IV 568/L 583). 22 For any possible world, there is a single world-space (or order of coexistence) and a single world-time (or order of succession) that delimit which substances can be members of that world. How exactly this is to be understood on Leibniz s mature 21 For a different reading of the passages from On the Ultimate Origination of Things, see Jeffrey K. McDonough, Leibniz and the Puzzle of Compossibility: The Packing Strategy, Philosophical Review 119 (2010), 135-63. McDonough distances himself from the cosmological account at pp. 141-2, n. 12. 22 See also T 8, T 201, and Causa Dei, 15: it is useless to invent a plurality of actual worlds, since one [world] comprehends for us the totality of created things in all times and places; and it is in this sense that we use the term world [mundi] (GP VI 440).
13 metaphysics is a point to which we will return in the next section. For the moment, it is enough to note that Leibniz s considered view of compossibility rests on the idea of a common spatiotemporal order, a point he illustrates with the example of fictional worlds such as that of More s Utopia. While the worlds described in such works are possible in themselves, they could not be part of our world because their inhabitants lack a spatiotemporal relation to us. 23 For a set of possible substances to be compossible, then, it is necessary that they be related via a common spatiotemporal order. This, though, is not sufficient, for Leibniz also requires that the members of the world be connected to one another. In the Theodicy, he states this as a condition that applies to any possible world: For it must be known that all things are connected [tout est lié] in each one of the possible worlds: the universe, whatever it may be, is all of one piece, like an ocean: the least movement extends its effect there to any distance whatsoever, even though this effect becomes less perceptible in proportion to the distance. (T 9; GP VI 107/H 128) By the universal connection of things, Leibniz means a mutual dependence among the states of substances, such that a change in any one substance is reflected in a corresponding change in every other. Although he denies that substances exert a real, or metaphysical, influence on one another, he holds that the members of a world condition each others existence, in the sense that they are causally related under a set of contingent laws. 24 This aspect of Leibniz s position is endorsed by the lawful interpretation; however, that account goes only part of the way in reconstructing the order of a world and the attendant idea of compossibility. The lawful interpretation highlights the dimension of order realized in the mutual 23 24 A VI.4, 1653-4/AG 94; GP II 181; GP III 572/L 661. A VI.4, 1646-7/AG 33; GP IV 510/AG 161; Mon 51-52.
14 causal dependence of created things, but does not acknowledge the significance of the spatiotemporal order that defines the capacity of a world and provides a framework for representing the causal relations of things. According to the cosmological account, any possible world possesses a distinctive form of unity that is determined by God s representation of the spatiotemporal order and causal connection that its members would have were that world to exist. Any two things are compossible, or members of the same possible world, just in case they are conceived by God as related in these ways. For Leibniz, then, a world is not merely a set or collection of substances; it is a unified whole that has a spatiotemporal and causal order analogous to those that unify the totality of actual things. Any possible world shares a formal structure with the actual world, and this structure conditions which things can coexist within it. A pressing question for this account is whether it is consistent with Leibniz s thesis of the maximization of perfection. If all possibles have a claim to exist proportional to their degree of perfection, why should we see God s creation as restricted to worlds in this sense? If God s consequent will is to produce the best, the greatest perfection or reality, why are spatiotemporal order and causal connection plausible constraints on the realization of that end? If it is possible for God to create more reality by abandoning these constraints, why wouldn t God do so? On behalf of Leibniz, we can reply, first, that we know that God has decided to create a world existences ordered by space, time and causation because such a world exists; hence, the creation of a world (in this sense) is an end for God, and we may suppose that his ultimate deliberation concerns how best to realize that end. Consistent with this, Leibniz maintains that God wills the creation of the world through a single volition that comprehends the whole order of the universe ; the object of his will is a unified series of things, not a set of discrete events or
15 existences. 25 Thus, although it would have been possible for God to have created more things realizing more total reality without the systematic order of a world, those things would fail to form a suitable object of God s will. To this the critic may reply that even if there exists this sort of limitation on the composition of a world, nothing prevents God from creating more than one world. Logically, the existence of one world-system does not preclude the existence of another. Why, then, does God not render all possible worlds actual? Although not all possibles can be created by God as one world, there is no logical restriction on the existence of a plurality of worlds. Thus, if God wanted to create all possible worlds, and hence the greatest possible reality, it seems that God could have done so. 26 This scenario can be blocked if we suppose that God has a unique will to create, and that consequently anything he creates must form part of a single comprehensive plan. Since different worlds reflect different plans, God would not will the existence of a plurality of actual worlds. 27 25 See T 84, and his letter to Ernst Hesse-Rheinfels for Arnauld of 12 April 1686 ( in order to proceed exactly, it is necessary to consider in God a certain most general and most comprehensive volition that he has with regard to the whole order of the universe, since the universe is like a whole that God penetrates in a single view ) (A II.2, 18-19/LA 15). 26 This concern is raised by Kointinen and Repo, Compossibility, 213-14. Kulstad interprets Leibniz as exploring this line of thought, inspired by Spinoza, in the paper De Formis Simplicibus, dated April 1676 (A VI.3, 522-3/Parkinson, 83-5). See Mark Kulstad, Leibniz, Spinoza and Tschirnhaus: Multiple Worlds, Possible Words, in The Young Leibniz and His Philosophy, ed. Stuart Brown (Dordrecht: Kluwer, 1999), 243-62, at 256-58. Several other texts from the period find Leibniz arguing against the idea of a plurality of actual worlds: A VI.3, 511/Parkinson, 65; A VI.3, 581/Parkinson, 103-5; A VI.4, 1349-50. 27 Compare his letter to Des Bosses of mid-october 1708 (Look-Rutherford, 112-13); and his letter to Arnauld of 16 July 1686: I think there was an infinity of possible ways of creating the world, according to the different designs which God could form, and that each possible world depends on certain principal designs or ends of God which are proper to it, that is, certain primitive free decrees (conceived sub ratione possibilitatis) or certain laws of the general order of that possible universe with which they are in accord and whose concept they determine as they do also the concepts of all the individual substances which must enter into this same universe (A II.2, 73/L 333).
16 This response falls short of a demonstration of the impossibility of the existence of all possible things and of the falsity of Spinoza s conception of God. In fact, following his initial engagement with Spinoza s metaphysics in 1676-77, Leibniz appears to have given little thought to the hypothesis of a plurality of actual worlds. He accepts that God creates one from among an infinity of possible worlds, because only in this way can he make sense of the belief that God acts as a just creator. The challenge for Leibniz is to reconcile this understanding of God with his modal metaphysics. If there were a presumption in favor of the actuality of many worlds, he would face a serious problem. However, if he can shift the burden of proof through a coherent account of compossibility, the most plausible creation scenario remains for him one in which God creates a single world from among an infinity of possible worlds. 4. The Best of All Possible Worlds Leibniz s view of the actual world as the best of all possible worlds is based on the perfection or reality realized in it: it is the world in which there is in actuality as much reality as possible (GP VII 306/AG 152). Yet the thesis is not a simple claim about the maximization of a scalar quantity of reality. Leibniz defines the possible, or whatever expresses essence or possible reality (GP VII 303/AG 150), as what is distinctly thinkable [distincte cogitabile] without contradiction (A VI.4, 558). Essences, or possible realities, are distinguished only insofar as they can be conceived as distinct by reason, from which it follows for Leibniz that a maximization of reality involves a maximization of different forms of reality. 28 28 There exists, therefore, that which is the most perfect, since perfection is simply quantity of reality. Further, perfection is to be located in form or variety (C 534/MP 146). Some of these forms are instantiated in individual substances, others in properties of things. With regard to the former, Leibniz asserts that no two substances can resemble each other completely and differ only in number, and that what Saint Thomas asserts on this point about angels or
17 Leibniz s commitment to the coextension of the real and the distinctly thinkable entails that the world containing the greatest reality is the world in which there is the greatest intelligibility, meaning the most to be understood (T 201). When asked by Wolff to explain his notion of perfection, Leibniz answers that it is the degree of positive reality, or what comes to the same thing, the degree of affirmative intelligibility, so that something more perfect is something in which more things worthy of being observed are found (GLW 161/AG 230). The intelligibility of the world is also a function of the order found within it, for order just is the distinct thinkability (distincta cogitabilitas) of many things in relation to each other. Things stand in such relations insofar as they are conceived by God as instances of general rules or principles (C 535/MP 146). Furthermore, Leibniz claims that nothing is more regular than the divine intellect, which is the source of all rules, and produces the most regular, that is, the most perfect system of the world, the system that is as harmonious as possible (GLW 171/AG 233). Consequently, the world of greatest perfection is also the world of greatest order and regularity, which produces the greatest agreement in variety and the richest object of intellectual contemplation. In short, Leibniz declares: Perfection is the harmony of things, or the state where everything is worthy of being observed, that is, the state of agreement or identity in variety; you can even say that it is the degree of contemplatibility [considerabilitas]. Indeed, order, regularity, and harmony come to the same thing (GLW 172/AG 233-4). 29 Such is the formal basis of Leibniz s theory of the best of all possible worlds. God creates the richest collection of beings, united by the greatest order, leading to the greatest harmony and intelligences (that here every individual is a lowest species [species infima]) is true of all substances (DM 9; A VI.4, 1541/AG 42). 29 Compare his comment to Bourguet: To be possible, intelligibility suffices; but for existence there must be a prevalence of intelligibility or order; for there is order to the extent that there is more to observe in a multitude (GP III 558).
18 the greatest range of opportunities for intellectual contemplation. Clearly, this is a very abstract way of representing God s ends in creation, and it does little to illuminate the connection between those ends and Leibniz s metaphysics of the created world. Within Leibniz s metaphysics, the formal attributes of perfection, which are the basis of God s choice of the best, are conveyed in a set of specific theses about elements of structure, design, and purpose, and multiple levels of harmony, that God realizes in creation. Above all, Leibniz aims to reconcile the idea that God creates the best possible world overall the world of greatest perfection and harmony with the idea that God has a particular concern to maximize the happiness of rational beings, who form the most important part of creation by virtue of their fellowship with God. 30 This is a complicated topic that encompasses almost all of Leibniz s philosophy. Here I can touch on only two significant points: the contrast between instantiations of order in the physical world and at the level of substances, and the contrast between order as realized in the world and order as understood and reproduced by minds. 31 Many of Leibniz s claims about the order of the created world refer to properties of physical laws. Most prominently, he argues that the laws of motion are contingent truths that cannot be explained on the basis of the concepts of space, time and matter alone, but require appeal to God s selection of the laws as the most fitting for a world: God s supreme wisdom has led him, above all, to choose laws of motion that are best adjusted and most suitable with respect to abstract or metaphysical reasons. The same quantity of total and absolute force, or of action, is preserved, the same quantity of respective force, or of reaction; and finally, the same quantity of 30 On God s multiple goals in creation, see DM 36; On the Ultimate Origination of Things (GP VII 306/AG 152-3); PNG 10; T 119, 124, 222. 31 For more on these issues, see Rutherford, Leibniz and the Rational Order of Nature.
19 directive force. [T]hese laws do not depend upon the principle of necessity, as do logical, arithmetical, and geometrical truths, but upon the principle of fitness, that is, upon the choice of wisdom. (PNG 11; GP VI 603/AG 210-11) Along with the laws of motion, Leibniz cites the laws of optics and the structure of matter (its infinite division and conformity to the principle of continuity) as examples of the order that supports God s choice of this world as the best. 32 Depending on how one construes the ontological status of the physical in Leibniz s philosophy, one may take these as first-order claims about the order God selects for the created world or as claims that point to a deeper account of order and harmony at the level of soul-like substances, or monads. On the latter reading, Leibniz s account of the fitness of the laws of nature concerns the order of a phenomenal universe that is the common object of the representations of perceiving substances. As early as the Discourse on Metaphysics, Leibniz describes God as creating a world of substances by actualizing an infinity of distinct perspectives on a single system of phenomena (DM 14). Producing substances in this way, God creates, as it were, an infinity of different universes, which are, nevertheless, only perspectives on a single one, corresponding to the different points of view of each monad. And this is the way of obtaining as much variety as possible, but with the greatest order possible, that is, it is the way of obtaining as much perfection as possible (Mon 57-58; GP VI 616/AG 220). Leibniz s description of the world as consisting of an infinity of perceiving substances, each expressing the same universe of phenomena from a unique point of view, fits neatly with his account of the formal attributes of perfection. It is a way of maximizing variety and the total quantity of reality, since it entails an infinity of points of view, each realized in a substance with 32 DM 19-22; GP IV 568/WF 123.
20 unique perceptual powers; and it is a way of optimizing order, since the perceptions of each substance are variations on a single template. The combination of maximal variety and optimal order makes it, by definition, the world of greatest harmony. A further point is worth noting about this scheme. In Leibniz s view, each monad is not just a perceiver of a phenomenal physical universe; it is also located in that universe by virtue of its relation to an organic body, which it represents as its own. Even if this body has no reality beyond its being the physical point of view of the monad, a trio of important conclusions follows. First, the states of every monad are spatiotemporally locatable relative to those of every other monad, via their representations of their respective bodies. 33 Second, every monad is confusedly omniscient, registering everything that happens in the universe, via its representation of its body and the causal connection of every other body to it. 34 Third, there are monads everywhere in matter, since every organic body uncovered in the infinite division of matter is the point of view of some monad. 35 While the correct interpretation of these theses is subject to debate, together they reinforce the connection between Leibniz s account of the order of the physical world and the order realized in the harmonious perceptions of monads. The basis of this connection is his conviction that in considering which substances to create, God conceives of them as little worlds [ses petits Mondes] (GP IV 557/L 576) that mirror in a limited form an archetype of the 33 C 14-15/MP 175-6; GP II 253/AG 178. 34 C 10; PNG 13; Mon 62. 35 Mon 66; Look-Rutherford, 24-5. For Leibniz, the last claim does not imply that matter is ultimately anything over and above monads, or that monads are literally spatially proximate to each other (cf. Look-Rutherford 227, 255). For discussion of these points, see Donald Rutherford, Leibniz as Idealist, Oxford Studies in Early Modern Philosophy 4 (2008), 141-90.
21 phenomenal universe represented in God. 36 This, in turn, allows us to give a more precise statement of the cosmological account of compossibility. Suppose, first, that the original conception of a world is that of a cosmos: a closed system of spatiotemporally and causally related bodies. Next, suppose that each of those bodies is identified as the point of view of a monad or is composed of bodies each of which is identified as the point of view of a monad. Then, any set of monads will be compossible just in case they are locatable in the same world: they represent themselves as parts of the same cosmos, with the result that there are determinate spatiotemporal and causal relations among any changes that occur in the contents of their perceptual states. To this account of the organization of a world, Leibniz adds a further critical claim about the place of rational beings in it. All created substances contribute to the perfection of the world through their own perfection and through the harmonious relations in which they stand to one another. Individually, rational beings contribute far more perfection than any other type of substance (Leibniz sometimes says infinitely more), but they also contribute perfection in a fundamentally different way, insofar as they mirror intellectually God s understanding of the perfection and order of things. 37 In short, while other beings contribute to the perfection of the universe merely by being parts of it, rational beings contribute by beings parts that are capable of understanding how all the parts, including themselves, are ordered in the universe. More than this, based on their understanding of order, rational beings are able to replicate that order through additions they make to the perfection of the universe. Thus, they understand, they plan, they 36 God contains the universe eminently, and the soul or unity contains it actually, being a central mirror, though active and vital, so to speak. Indeed, we can say that each soul is a world apart, but that all these worlds agree, and represent a different relation to the same phenomena. And this is the most perfect way of multiplying beings as far as possible, and in the best way possible (GP III 72/WFN 132). Cf. DM 9. 37 DM 35; Mon 83.
22 construct with all of this order-creating activity being conceived by God as part of what makes this the best of all possible worlds. Finally, and most importantly, rational beings have the capacity to understand the special place they occupy in creation, as citizens of the city of God, and how their role replicates the role that God plays with respect to creation as a whole. 38 That is, they are able to grasp reflectively that they are beings who understand order and have the capacity to produce order in the universe, just as God has brought into existence the world in which the greatest diversity of things is ordered in the most fitting manner. The last two points highlight an essential feature of Leibniz s doctrine of the best of all possible worlds. It is mistake to think of this title as earned on the basis of the present state of the world, or indeed any finite state of it. The claim of this world to be the best rests in large part on its potential to grow in perfection indefinitely, through the intellectual and moral development of minds and the additional order and harmony they introduce into the world. With this comes the possibility of unending increases in human happiness. 39 The potential for progress of this sort is what gives Leibniz the greatest confidence in affirming this as the best of all possible worlds in the face of innumerable examples of ignorance, weakness and cruelty that seem to count against this description. 5. Creation, Conservation, Concurrence God s involvement in the actual world does not end with creation. God s plan for the world embraces the totality of its history. Beyond this, though, Leibniz argues that God is directly implicated, as cause, in the continuation of the world s existence from the moment of its 38 GP VI 507/AG 192; PNG 14-15; Mon 84-86. 39 See On the Ultimate Origination of Things (GP VII 307-8/AG 154-5). The contributions minds make to this progress is also the source of their greatest happiness (PNG 18).
23 creation. The omnipotence that is necessary to bring things into existence is equally necessary to sustain their existence. In the Principles of Nature and of Grace, Leibniz writes: The reason that made things exist through [God], makes them still depend on him while they exist and bring about their effects; and they continually receive from him that which causes them to have any perfection at all (PNG 9; GP VI 603/AG 210). Suggested in this passage are three central theological doctrines: (i) God conserves the things he creates, sustaining them in existence; (ii) this conservation amounts to a continual creation, whereby things receive from God throughout their existence whatever perfection is in them; (iii) the dependence of created things on God extends to all the effects brought about by them, with the result that nothing happens in the world without God s concurrence in the production of those effects. Leibniz aims to show that these doctrines are consistent both with the main claims of his theodicy and with his metaphysics, according to which the primary existing things, substances, are genuine secondary causes indeed, spontaneous causes of all the changes in their own states. 40 The first doctrine is embraced by all seventeenth-century philosophers. No finite thing is a causa sui; it does not exist of itself. It exists only because it has been created by God, and the fact that it exists now in no way diminishes its dependence on God for the continuation of its existence. Rather, God must actively conserve its existence (T 385). According to the second doctrine, this dependence consists in a thing s receiving from God, throughout its existence, whatever perfection is in it. For Leibniz, this is what it means for a 40 For treatments of these issues, see Robert C. Sleigh, Jr., Leibniz and Arnauld: A Commentary on Their Correspondence (New Haven: Yale University Press, 1990); Robert M. Adams, Leibniz: Theist, Determinist, Idealist; Sukjae Lee, Leibniz on Divine Concurrence, The Philosophical Review 113 (2004), 203-48; Jeffrey K. McDonough, Leibniz: Creation and Conservation and Concurrence, The Leibniz Review 17 (2007), 31 60.